With Christian psalms, Hindu Upanishads and the word according to Rudenstine, the senior class will join in worship today in the Baccalaureate service at Memorial Church.

A medieval Christian rite transformed for today's secular Harvard, the service aims for interfaith inclusion.

Capped and gowned, seniors march from the Old Yard to Memorial Church behind the Class marshals and various religious and university officials, slowly crowding Memorial Church to stand waiting in the pews for the president's cue to sit.

The worship starts with a salutation from Pusey Minister in the Memorial Church and Plummer Professor of Christian Morals Peter J. Gomes.

Selections from Harvard's diverse religious traditions follow, with seniors reading from the Bible in Hebrew, the Upanishads in Sanskrit, the Koran in Arabic and the New Testament in English.

Preceded and followed by Christian hymns and prayers, President Neil L. Rudenstine will address the class with a modern take on the antique tradition of Harvard's Baccalaureate sermon.

Seating inside Memorial Church for the popular event is reserved for seniors. Parents, family members and spectators must stay outside in Tercentenary Theater, where loudspeakers broadcast the service.

Among those outside will also be the few seniors who, because of their religion, cannot join the celebration inside.

Some Orthodox Jews hold that the laws of their faith prohibit their entering a church.

Jonathan X. Gruenhut '00, one such student, says he won't be with his class at the service. Instead, he will sit among the spectators in folding chairs on the lawn.

Despite their exclusion, the Orthodox community has not made an issue of the Christian venue.

" I don't know of any people who are angry about it, including myself," Gruenhut said.

Orthodox community members, for the most part, say they do not resent the fact that Harvard holds the service in a church. They view their situation, instead, as an unfortunate inconvenience for some observers of Jewish law.

Nor do the seniors who sit the service out find fault with its content.

"I think it's basically a value-neutral message. Memorial Church is not known for its Christian fundamentalism," Gruenhut said.

The tone of interfaith understanding is a relatively recent development in the history of the Baccalaureate.

The service finds its roots in the medieval period at the commencement of Cambridge University.

During the first Baccalaureate sermons, monastic devotion was expected of a candidate while he "sat with bowed head over which his hood was drawn, a picture of abject humility and utter embarrassment," according to Cambridge's 13th-century statutes as quoted by Gomes in the Baccalaureate service's program.

The tradition was carried across the Atlantic to New England and figured in Harvard's first Commencement in 1642.

In a strict Puritan society, Commencement was a rare chance to celebrate, and residents of surrounding towns mobbed Cambridge.

The days before Commencement were given over to drunken revelry, but the spiritual oratory served as counterpoint to less solemn activities like attacking student theses and gorging at feasts.

An 18th-century observer, describing a typical commencement, derided the stodginess of the sermon with a sarcastic comment.

"[It] goes off brilliantly, that is to say, nobody gets depressed," he said.

The first preserved example of a Baccalaureate sermon was given to the Class of 1794, delivered by Hollis Professor of Divinity David Tappan.

No doubt appalled by Commencement's characteristic overindulgence, Tappan chose to discuss a verse from Paul's Epistle to Titus: "Young men likewise exhort to be sober-minded."

The preacher's exhortation warned against the peculiar susceptibility of Harvard's young men to the influences of "heathen classes" and reminded them of the benefits of sobriety.

"This is the sure, the only path to dignity and honor," Tappan said.

With the 19th century began the practice, still maintained, of singing Psalm 78 at each sermon to the tune of "St. Martin's."

The choice of speaker has always belonged to the seniors and from the 19th century until today, they have always invited the University president to preach.

With laypeople at the pulpit, the service moved away from strict liturgical sermonizing to more secular concerns. Often, the president used the gravity of a religious service to underscore universal ethical concerns.

President A. Lawrence Lowell, Class of 1877, who stated his religion as "universal" and commended Islam, gave the sermon from 1910 until 1933 but still prefaced each speech with a Biblical verse.

The Baccalaureate sermon then became called the Baccalaureate address, dropping the last vestiges of Puritan preaching.

The present program of readings from outside the Judeo-Christian is a recent tradition begun during Gomes' tenure.